What is called circular turning point?

A circular turning point refers to a specific position in a dynamical system where an object, like a planet or a satellite, reaches a state of stable circular motion around a central body, such as a star or planet. At this point, the gravitational force acting on the object is balanced by the centrifugal force due to its circular motion, allowing it to maintain a stable orbit. In the context of general relativity, it can also refer to a point in a gravitational field where trajectories are closed loops.